By LARRY LANGE, P-I REPORTER

Updated 10:00 pm, Wednesday, January 31, 2007

The Alaskan Way Viaduct probably won't be replaced by a six-lane tunnel -- but the state will at least take a look at a four-lane version favored by Seattle Mayor Greg Nickels.

In a letter Wednesday, Gov. Chris Gregoire and legislative transportation leaders asked the state Department of Transportation and a panel of experts to answer nearly two dozen questions about the four-lane proposal's safety, and whether it and Alaskan Way can handle 137,000 vehicles expected daily by 2030, as projected by the mayor.

A completed review is aimed for Feb. 13, a month before Seattle residents cast advisory votes to express their preference for a new, elevated highway or the four-lane tunnel.

The study is designed to give city voters more information than they have currently, department officials said Wednesday.

"There are a lot of questions left unanswered," said Gregoire spokeswoman Holly Armstrong.

But it's still not clear if the vote will affect how Gregoire and legislators decide how to replace the viaduct, which state engineers fear could collapse in another major earthquake.

Among the other questions to be answered before Feb. 13 are:

Whether the federal government, which is contributing more than $200 million toward a tunnel, will accept using the shoulders of a four-lane facility to carry traffic during rush hour, as the proposal calls for.

Whether emergency-service providers are concerned about their vehicles' access to shoulders during rush hour.

Whether a smaller tunnel will divert traffic to Interstate 5, and whether it requires another environmental impact study.

How the four-lane tunnel would affect freight and bus movement through the state Route 99 corridor.

The letter asks the viaduct Expert Review Panel, convened originally last summer, to analyze the cost of the four-lane tunnel and compare that with the price tag for a new elevated highway "using common scheduling and other cost-savings assumptions."

Gregoire also ordered the Transportation Department to "suspend work on the current six-lane cut-and-cover tunnel alternative," given the abandonment of it by Nickels and most City Council members.

The new study was a partial win for Nickels, who pushed for a state review of his proposal in mid-January. Nickels and City Councilwoman Jan Drago said they think the new analysis can be done by mid-February.

"It's vital that voters have the most complete and accurate and reliable information when they make this choice," said Nickels spokesman Marty McOmber of the study and the ballot. "The future of our waterfront is at stake."

Transportation Secretary Doug MacDonald, who heads the state DOT, said "we're just going to have to see what we can do (the work) in the time that's available to get it done."

At a Senate committee hearing last week, a DOT official estimated an analysis of the tunnel would take three to four months. Both Armstrong and Rep. Judy Clibborn, D-Mercer Island, chairwoman of the House Transportation Committee agreed Wednesday that the two-week analysis won't be as detailed as the one discussed.

Clibborn also said the developments mean the six-lane tunnel proposal is probably dead.

"Seattle put a fork in it," she said. She said the February study will give lawmakers more information to use when they decide what to do about the viaduct. She wouldn't say the development was a win for Seattle, given its past inability to raise money for the larger tunnel.

House Speaker Frank Chopp, a strong tunnel opponent, said reconvening the review panel would only strengthen his position.

The description of the four-lane tunnel so far "is not a fair representation of the costs or risks, or the closure time, or the safety standards or the capacity issues," he said.

John Fox, co-chairman of an anti-tunnel group, said he also thinks the new study will show the proposal's shortcomings. "Bring it on," he said.